I think that the clamp overlap is doing what it is supposed to do -- let the bevel go as far as it can before geometry bumps into other geometry, and no further. Only it is doing it "better" than it used to: it used to be very conservative and not go nearly as far as it could sometimes (which various users reported as bugs), and I put in code to do a better job of that in rBb2392afc5036 ,

Now, because it lets the bevel go right up until it hits other geometry, it creates zero-area faces and overlapping edges, which no doubt is what is causing the artifacts you now see.

I suppose one thing I could do is stop it at, say, 95% of the value that would cause overlap. But that has the disadvantage that maybe people want to go right up to collision (and then merge stuff)?